Philae lander separating from Rosetta and descending to the surface of comet 67P/Churyumov-Gerasimenko in November 2014.Credit: ESA/ATG medialab

Target: Comet 67P/Churyumov-GerasimenkoCredit: ESA/DLR

Europe’s Rosetta lander will soon dispatch the Philae lander in the hopes of making a spot-on touchdown on Comet 67P/Churyumov-Gerasimenko.

But where to land?

The site needs to be at a level yet scientifically interesting location, with enough sunlight and the right conditions to ensure a long working life.

However, the rugged, unusually shaped comet is not making the choice easy for the lander team, a consortium of experts led by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).

The group has until August 24 to choose up to five potential landing sites. Once that’s done, detailed appraisals of each site can be conducted.

The candidate sites will be announced on August 25.

First ever landing

On November 11, the lander component of the European Rosetta mission, which is controlled and operated by the DLR Lander Control Center (LCC), is scheduled to carry out the first ever landing on a comet.

According to the DLR, the initial selection of no more than five potential landing sites is hard enough.

The comet, which consists of two connected parts, offers only a limited number of level, uniform surfaces on which Philae could land safely.

The “landing ellipses”, within which the actual landing site lies, have a radius of around 500 meters:

As a control signal from Earth takes over 30 minutes to reach the lander, Philae must take care of the landing by itself, automatically, using a procedure pre-programmed by DLR and with no real-time corrective actions from the Control Center.

Therefore, the lander team is anxious to avoid regions with large boulders, rock or fissures, to reduce the risk for the Philae lander as much as possible, Ulamec said in a DLR press statement.